In many parts of the country, winter-like conditions deposit or form snow and ice on structures, such as roofs of buildings. As a result, snow and ice can pile up on a variety of structures, including roof eaves and intersecting valley areas of roofs. The accumulated volume and weight of ice and snow can cause serious, costly damage to the roofing and other structures.
In addition, as snow and ice melt (typically during the daytime), the resulting flow or dripping of water down or from the roof can form a wide variety of dangerous icicles and ice structures as temperatures later drop (typically in the evening and at night). The resulting icicles and ice structures often fall off the roof or other structure and cause serious damage to property as well as humans and animals.
Often, ice dams forms along roof eaves and intersecting valley areas. Such ice dams can form when: (1) snow accumulates on a roof; (2) heat escapes from the building's interior and melts accumulated snow; and (3) outside ambient temperatures are below freezing, which can cause the melting snow from the heated area to re-freeze along a cold overhang of the roof.
Ice dams can cause a wide variety of serious problems. For example, they can create standing water conditions above the ice dam at a roof overhang. This standing water can cause a variety of types of damage, whether due to weight of the water on the roof or water leakage into the structure or by sliding off of the roof.
These serious and dangerous problems obviously have existed for a very long time. A variety of electrical systems have been developed in the past to try to solve them.
In one prior art electrical system, a heat generating cable is placed along the roof edge, valleys, and other locations. Commonly, the cable is laid in a zig-zag configuration and is exposed and visible on the roof top. With such systems, much of the drip edge area remains unheated and can accumulate dangerous icicles and ice formations. Further, the cable is exposed to the elements, thus leading to ultraviolet degradation of the cable over time. The cable also typically is secured to the roofing by clips that are in turn fastened to the roofing by fasteners penetrating the roof. Commonly, these fasteners are also exposed, creating the risk of leaks. Heater cable can often be stripped off the roof by high winds or sliding snow.
One prior art system, the Bylin RIM System, consists of a single aluminum heating element mounted to a roof edge and a metal panel cover mounted over the top of the heating element. One lateral side of the heating element abuts and surrounds to some degree the roof edge, and the panel cover typically surrounds heating element, including a portion of the lateral side of the heating element surrounding the roof edge. The panel cover then extends upwardly across and in contact with the upper sides of the heating element and past the heating element upwardly along the roof. The upper portion of the panel cover extending upwardly along the roof is commonly secured to the roof by (i) mounting the upper panel portion on a section of the roof to be further covered by roof structure such as shingles, (ii) securing upper panel portion in place with fasteners penetrating the upper portion and roof support structure below, and (iii) then covering the upper panel portion by mounting shingles over it. A heating cable is mounted in serpentine fashion within three cable passages running along the entire length of the heating element. Thus the three lengths of heating cable heat the aluminum heating element, which in turn heats the panel cover to melt ice and snow in contact with cover.
The applicant has discovered and believes that the heating element of the Bylin RIM System presents a number of problems. They include, for example, that its heating element consists of two relatively thin, planar upper panel support and contact sections spanning between three spaced-apart heating cable channels extending downwardly from the upper panel support sections, and the downwardly extending channels also include, at their lower ends, planar roof contacting sections extending laterally from the lower ends. The relatively thin upper panel support sections, which span across the top of the heating element, can unduly warp, provide insufficient support to, and less than optimal contact with, the upper cover panel cover, and also insufficiently transfer heat through these sections to the upper cover panel. Also, the planar roof contacting sections provide heat loss by consuming heat themselves and also transferring heat to the supporting roof structure in contact with these planar roof contacting sections. In addition, this system provides less than possible heat transfer to its lower edge, which also is in contact with and intended to heat the lower edge of the upper cover panel surrounding that edge to a substantial degree. Further, by providing so much contact between the heating element and underlying roof structure, this system can cause water and humidity to build up in that contact area over time, leading to various problems such as dry rot of adjacent roof materials and corrosion or loosening of the roof attachment fasteners securing the heating element fasteners to the roof.
In another somewhat similar prior art system, by Thermal Technologies, includes a sizeable aluminum heating element that has both a substantial top and a substantial bottom section. The bottom section is secured to the roof by fasteners. The top section has two downwardly extending arms that clip within mating upwardly facing slots along the length of the bottom section. The top and bottom sections cooperatively provide four heating cable passages. Two of the passages are sized to accept one size of heating cable. The other two passages are adapted to accept a differing size of heating cable.
The applicant has discovered and believes that the Thermal Technologies system presents a number of problems too. For example, it is heavy and material intensive, which not only requires excess material costs but also adds weight to the structure and stress on associated supporting structures. Also, when heater cable is mounted within it, its upper and lower heating element sections are spaced apart by the heater cable, and this leads to substantially reduced, or at least less than optimal, heat transfer from the heater cable to and across the upper heating element section as well as to the portions of the lower heating element section that contact the upper cover panel. In addition, the lower heating element section of this system has a large lower surface in contact with the underlying roof structure, causing heat loss by heating of this structure as well as by heat transfer to that contacting underlying roof structure. Further, this system also provides less than possible and desired heat transfer to its lower edge, which also is in contact with and intended to heat the lower edge of the upper cover panel surrounding that edge to a substantial degree.
Other problems with this system include, for example, its upwardly facing slots, into and through which water can leak and debris can accumulate, which can cool the heating element, reduce its heat transfer efficiency, and cause accelerated rotting of the heating cable. Similarly, by providing so much contact between the heating element and underlying roof structure, this system can cause water and humidity to build up in that contact area over time, leading to various problems such as dry rot of adjacent roof materials and corrosion or loosening of the roof attachment fasteners securing the heating element fasteners to the roof.